1. Field of the Invention
The invention relates to electronic devices. Specifically, the invention relates to apparatus, systems, and methods for conserving power used by an electronic device.
2. Description of the Related Art
Conventional users have high expectations for today's electronic devices. The user expects their computer, Personal Digital Assistant (PDA), laptop, tablet, game device, and other electronic device to provide a bright, vivid, color screen, a highly responsive processor, and a high quality stereo sound. These features generally consume large amounts of power.
Even if power is readily available, such as when using a conventional power outlet, certain users also expect the electronic device to conserve power as much as possible. Power conservation is particularly important for portable electronic devices such as laptops, PDAs, tablets, and the like. Batteries for portable electronic devices are unable to provide bright screens and highly responsive processors for more than a few hours before the batteries are exhausted. Short battery life can severely limit the portability of a portable electronic device.
Accordingly, power management systems have been developed, particularly for portable electronic devices such as laptops, which extend the useable life of the batteries. Generally, these power management systems reduce or turn off power flow to certain subsystems of the electronic device. Typically, the power is reduced or shut-off in response to inactivity of the subsystem. For example, if no files have been accessed for a predetermined length of time, the disk drive(s) may be shut-off or the platters of the disk drive(s) may be allowed to spin-down. Similarly, if an Input/Output (I/O) device such as a keyboard, mouse, touch screen, or the like has not registered an input from a user for a period of time, high power consumption subsystems and/or circuits may be powered down.
Conventional power management systems use internal timers which begin counting down once there is a lack of input from a user or lack of activity for certain subsystems. Generally, to avoid constant powering up and powering down of subsystems, the timers are relatively long (typically 1 to 5 minutes) to account for normal user inactivity in relation to the electronic device. However, if a user is not even in close enough proximity to use the electronic device, the delay until the timer expires unnecessarily wastes power.
In addition, lack of input from a user may not mean the user is not using the electronic device. For example, a user may be studying a complex figure or reading a large quantity of text on the display such that a timer expires and the power management system dims or shuts down the display. Such behavior can quickly annoy a user and may cause a user to increase the timers, which may waste more power when the user is not present.
Conventional power management systems manage power based on the presence or absence of a user. Generally, in these systems, some form of presence sensor detects whether a user is in close proximity to the electronic device. If so, the power management system may continue to power certain subsystems, even if a timer has expired.
Unfortunately, the presence or absence of a user does not provide sufficient information for effective power management. For example, a user may be positioned in front of a laptop at his/her desk studying documents instead of using the computer. In such an instance, conventional presence detection oriented power management devices continue to power subsystems such as an LCD display, even though the user is not viewing the display.
In addition, conventional power management systems, both timer based and presence detection oriented, generally transition between a full power state and minimal power state (only presence sensors powered). Such a transition incurs a delay when the subsystems are powered up or powered down. This delay is referred to herein as latency, and may range from several seconds to a couple of minutes. Users have come to expect an immediate response from electronic devices, and latency delays of several seconds may cause users to avoid or disable such power management systems.
Furthermore, as portable electronic devices are carried about and used, power management systems that rely on presence detection may incorrectly register the presence of a user. For example, as a PDA or tablet is carried, a user's hand may be incorrectly interpreted as a user prepared to interface with the device. Consequently, power may be needlessly wasted.
Accordingly, what is needed is an apparatus, system, and method for adjusting power use in an electronic device naturally, such that power is shut-off and restored to subsystems in response to movements of a user in relation to the electronic device. The apparatus, system, and method should adjust the power level between a plurality of power levels to minimize power-up and power-down latency. In addition, the apparatus, system, and method should manage power based on indications from a user beyond simple presence or absence to optimize power use. The apparatus, system, and method should adapt power management to the use habits of the user.